How to Deal with Weeds

20 July 2012, written by Benedict Vanheems

They're the bane of every kitchen gardener's life and they seem to appear the moment your back is turned. I'm talking about weeds of course! I recently tried to work out exactly how much time I spend weeding – either on my haunches plucking weeds one by one from between my veg, or slicing (or, rather, gliding!) back and forth with the hoe. Perhaps unsurprisingly the answer I came to was 'a lot' of time.

By the middle of summer you will either have managed to keep your plot pristine or the weeds may well be gaining the upper hand. Hopefully you are in the former camp, but even if the weeds are growing thick and fast it's never too late to whip your plot back under control. The secret – and this can't be emphasised enough – is to never let those weeds get out of hand again. There's absolute truth in the old adage 'seven year's seeding means seven year's weeding'.

Weeds can be divided into two known enemies: the annual weeds that set seed in a blink of the eye, often in as little as three or four weeks, and perennial weeds, which will spread primarily by stealth means, creeping along using rhizomes, roots and by layering. Both types of weed need to be tackled in slightly different ways.

Bittercress

Annual weeds

The trick with annual weeds such as chickweed, bittercress, fat hen and groundsel (to name just a few) is to snuff them out while they're still young. Just-germinated seedlings can be tackled with ease by dislodging them with a sharp hoe. Compare this with fully grown weeds and it's easy to appreciate why tackling them at this stage is preferable! Get into the habit of checking over your vegetable garden at least every other day. It can feel like weeds are resolute in their determination to surface but every weed removed is one less seed in the soil's weed seed bank. Eventually your ground will become relatively clean of weed seeds and the job will become much easier, though of course you'll always need to be on hand to deal with weeds coming in off wind-blown seeds.

Play detective – look under the leaves of crops and pull out any lurking weeds. It may be a bit of a faff climbing in among the undergrowth but it will keep weeds from flowering and pay dividends in the future. Always think at least one crop ahead. The current crop may take the weeds in its stride with no ill effects on what you harvest, but what about the next crop? If you leave those apparently harmless weeds to their own devices they will only set seed and render the vegetables that follow a challenge.

Mulching between plants with well-rotted (and clean!) organic matter won't just suppress annual weeds by suffocating them before they've got going, it will gradually improve the structure of your soil, making it fluffier and easier to extract those weeds that do appear. In time you will move towards a fertile soil that's low in weed seeds and that favours your crops, not the likes of sow thistles or willowherb!

Perennial weeds

Rambunctious perennials such as bindweed, couch grass (twitch/quick grass), nettles, dandelions and ground elder get something of a bad press. But while at first glance they might appear to be insurmountable, you can and will eventually win the war of weeds over these guys!

Where individual perennial weeds or manageable clumps exist there's no better remedy than digging them out with a trusty fork. While some perennials can re-sprout from the tiniest fragment of roots and require meticulous picking over to remove every last morsel (couch grass, bindweed, horsetail), others are more forgiving and will die so long as their main root is removed or severed deep down (nettles, docks, brambles). Roots of pernicious creeping weeds can be drowned in a bucket of water before the resulting slop is added to the compost heap.

Bindweed. Photo credit: amandabhslater

I'm often asked by disheartened gardeners what the solution is to a thick mat of perennial weeds. The solution here is time – and plenty of black polythene. Hack back the worst of the top growth (this can be put onto the compost heap), add a layer of compost or well-rotted manure over the remaining stubble then cover the whole lot with thick black polythene. The polythene has to be black to exclude the light. It will weaken the weeds beneath over time, causing them to fail and rot down into the soil along with all that organic matter. Keep the polythene in place for at least a year then dig over the now weed-free soil. The ground needn't be wasted space over those 12 months – lay growbags and containers over the surface and plant into these instead.

Speedy conversion

If you want to convert a weedy patch that isn't full of really pernicious weeds you may get away with covering the soil with cardboard before adding a 10-15cm (4-6in) layer of compost on top. This can then be used to grow your crops while the weeds beneath are suffocated by the cardboard. The cardboard should rot down within a season, remaining intact just long enough to see off the grass and weeds beneath.

If there's one take-home message from all of this, it's that persistence does pay – I promise! Keep on top of the weeds and don't let them bully you into submission. Catch them while they are young, remove all roots of persistent perennial weeds and never, ever let annual weeds set seed.

Comments

"Can you use newspaper instead of cardboard? I was thinking of laying down a thick layer of newspaper and topping with compost. And then seeding in the fall."Bretton Friday 20 July 2012

"Hi Brett. You can indeed use newspaper. I'd lay it fairly thickly, as you suggest - about 10 sheets thick should to the trick. Good luck with your project!"Benedict Vanheemson Friday 20 July 2012

"I am currently reading WEEDS:In Defense of Nature's Most Unloved Plants by nature writer, Richard Mabey. It is chock full of the history and use as food of what most consider nothing more than an annoying bane of gardeners.
Weeds are quick to follow on the heels of cultivated plants and even adapt ways by which to survive (sometimes via mimicry) among food crops.
Perhaps we ought to reconsider, in even some small way, our stance as enemies...
Tender young dandelion leaves are a delicious addition to the salad bowl - with the hint of bitterness that we love in cultivated arugula! If it is both nutritious and free for the taking why destroy it?
GardenMuse912DJW in Virginia, USA"DR-Ton Saturday 21 July 2012

"Is this one edible?
http://tinyurl.com/cvqruob
If so, I have TONS of it which has basically carpeted the 1st phase of my garden. When I was on top of weeding, I would feed this to my chickens. But in this heat (Phoenix), I've stopped weeding and plan to just suffocate it before my fall planting."Bretton Saturday 21 July 2012

"I've given up trying to find the black polythene we see on so many plots. Other gardeners seem to manage to obtain massive squares of the stuff. Where on earth are they getting it ? :-o "snowdropson Sunday 22 July 2012

"There are many good wild food reference guides available: check your local library or bookstore to find one that is good for use in your area of the world.
Going online can be helpful but sometimes requires further research because of incorrect image, colloquial names and plain old fashioned misinformation.
Euell Gibbons, is among the most respected authorities: Stalking the Wild Asparagus is his best - but may be difficult to find...that's why I suggest you begin researching at the library or through your local agricultural extension service.
Bittercress and nettles are edible...whether you enjoy them is strictly a matter of one's palate! Garlic, lemon juice and olive oil seem to do the trick for me.
GardenMuse
"DR-Ton Monday 23 July 2012

"I just had a knowledgable guest here at my farm who when touring my farm garden (to which I'd just placed 3" of composted sawdust acquired from the local sawdust pellet company down the road) had this advice, "Only use shavings from the bark of the Douglas Fir, as all other wood fibre products acutally LEACH NITROGEN from your soil." Does anyone know more this? "Paula Shackletonon Monday 23 July 2012

"Someone suggested I use old carpet like a weedmat idea. Then compost over the top. The carpet apparently breaks down over a number of years. Haven't given it a go yet. Has anyone else tried this with success?"Jackieon Friday 3 August 2012

"Hi Paula. Sawdust can indeed draw nitrogen from the soil as it decomposes, so always use sparingly or in combination with a high-nitrogen fertiliser. Of course, once the sawdust has fully decomposed the nitrogen will be returned to the soil."Benedict Vanheemson Tuesday 7 August 2012

"Hi Jackie. Old carpet is no longer recommended for covering the ground as it may contain harmful chemicals that would be leached into the soil. The exception is carpets/rugs made from truly organic materials such as hemp, coir, jute, seagrass, sisal, wool etc. and with natural dyes. Even natural carpet can take a few years to decompose, so if you are adding compost on top, I would use materials that break down quicker, such as sheets of old newspaper or cardboard."Benedict Vanheemson Tuesday 7 August 2012

"What a very impressive post. I am glad for the share. Now that you mention it, I guess I should allocate a space for hoe test. I really don't have one. Wow its a very good post. The information provided by you is really very good and helpful for me. Keep sharing good information.. "rohiton Thursday 16 August 2012

"Hi Rohit. That's very kind of you to say, thanks for the encouragement! Do invest in a hoe - I promise you you'll be so glad you did once you've had it a while. It saves time and, importantly, your back!"Benedict Vanheemson Monday 20 August 2012

"What about a combination of 20% vinegar and orange oil to kill weeds down to the roots?"Jerryon Tuesday 22 March 2016

"Vinegar solution has been advised for awhile, but is being withdrawn. Not good in the long run."K Gon Wednesday 15 June 2016

"RE: Using newspaper as a weed control: Doesn't printer's INK in newspaper contain toxins ???
Secondly, Thankyou to the person who advised that though pure wool carpets are biodegradable, the dyes may be toxic.
Other (organic gardening) sites appear to ignore the question of dyes.
Question: I imagine ALL the dyes used in wool carpet are toxic ? And possibly OTHER chemicals are added for moth control etc. ?? Can anyone answer these questions? Thankyou !
"Carolyn Fraseron Friday 13 January 2017

"Hi Carolyn. Newspapers nowadays use soybean oil as the basis for their ink, which is much safer in the environment. Guidelines for organic gardeners state that newspapers are safe to use in the garden. The big caveat is that paper from glossy magazines should definitely be avoided. Only use non-shiny, standard newspaper paper.
With regards using carpets, the secret is to use only carpets and rugs that are made of natural fibers such as woold, cotton or jute. These will biodegrade without harm. Synthetic carpets are treated with chemicals and cleaners, which could leach into the soil. "Ben Vanheemson Monday 16 January 2017

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